Device manufacturing method

Abstract

An insulating film is formed on a semiconductor substrate and a photoresist film is formed on the insulating film. The photoresist film is patterned so that a first mask pattern including a thin film portion is formed. A photoresist film is formed over the first mask pattern so as to cover the thin film portion. A second mask pattern is formed by patterning this photoresist film and, at the same time, a portion of the photoresist film is left on the thin film portion. The insulating film is processed using the first and second mask patterns.

What is claimed is:  
     
         1 . A device manufacturing method comprising the steps of: 
 forming a first mask film on an underlying portion;    forming a first mask pattern including a thin film portion by patterning said first mask film;    forming a second mask film on the first mask pattern so as to cover said thin film portion;    forming a second mask pattern by patterning said second mask film and leaving a portion of said second mask film on said thin film portion; and    processing said underlying portion using said first and second mask patterns.    
     
     
         2 . The device manufacturing method according to  claim 1 , wherein 
 said step of patterning the second mask film includes the step of forming said second mask pattern so that the second mask pattern becomes a pattern of the same form as of said first mask pattern.    
     
     
         3 . The device manufacturing method according to  claim 2 , wherein 
 said first and second mask films are photoresist films, and    said second mask pattern is formed using the same photomask as a photomask for the formation of said first mask pattern.    
     
     
         4 . The device manufacturing method according to  claim 1 , wherein 
 said step of patterning the second mask film includes the step of patterning said second mask film so as to leave said second mask film on only the thin film portion of said first mask pattern.    
     
     
         5 . The device manufacturing method according to  claim 4 , wherein 
 said first mask film is a positive-type photoresist film, and    said second mask film is a negative-type photoresist film.    
     
     
         6 . The device manufacturing method according to  claim 1 , comprising the step of 
 forming a hardened layer on a surface of said first mask pattern after said first mask film is patterned.